• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.23-29
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• 1997

유한요소법을 이용하여 경수로형 핵연료집합체에서 냉각수 유동에 의한 수직 상승력으로부터 핵연료를 지지하는 판형 HDS의 강성도를 수치해석적으로 평가할 수 있는 방법을 제안하였다 I-DEAS code의 8 node brick element를 사용하고 판스프링들간의 간섭 부위에 접촉요소를 사용한 유한요소 모델링 및 해석기법으로 평가한 탄성강성도가 변형 에너지법에 근거하여 유도된 탄성강성도 평가식으로부터 얻은 결과와 잘 일치하고 있어서 제안된 유한요소 모델링 및 해석기법은 판형 HDS의 거동 분석에 유용하게 이용될 수 있다.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.223-232
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• 2003

In this study, a constitutive model called the disturbed state concept (DSC) was modified to be applied to the interface shear stress-displacement relationship between geosynthetics. The DSC model is comprised of two reference states, namely the relative intact (RI) and the fully adjusted (FA) state, and one function, namely the disturbance function. This model is a unified approach and can allow for various models as an RI state such as elastic-perfectly plastic model, hierarchical model, and so on. In addition, by using this model, the elastic and plastic displacements can be considered simultaneously. Comparisons between the measured data and predicted results through the parameters determined from four sets of large direct shear tests showed good agreements with each other, especially for the smooth geomembrane-involved interface. Although there are slight differences at peak shear strength for textured geomembrane-involved interface, this model can still be useful to predict the position of displacement at peak strength and the large displacement (or residual) shear strength.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.1-8
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• 2006

Effective three dimensional modeling becomes essential in a wide range of drawings, such as construction, machinery and design. In particular, it has been developed as the tool enabling reverse design. Three dimensional modeling requires rapidity, accuracy and tangibility. Data acquisition methods for modeling including contact type coordinate measurement machine, LASER scanner, pattern scanner and digital photogrammetry. In this study, we try to analyze modeling techniques as well as introduce three dimensional modeling using pattern scanner. In addition, this study conducts three dimensional modeling using OPTO-Top pattern scanner with distinguished accuracy and rapidity, and then compare efficiency with digital photogrammetry. And, this study attempts to form environment that enables to turn around models on web in three dimensional ways.

• Explosives and Blasting
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• v.23 no.3
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• pp.27-42
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• 2005

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). The stress wave propagation modeling was conducted by simulating the experimental approach based on the Hopkinson's effect combined with the spatting phenomenon that had previously been developed to determine the dynamic tensile strength of Inada granite. As a result, the stress wave velocity obtained by the proposed modeling technique was 4167 m/s, which is merely $3\%$ lower than the actual wave velocity of 4300 m/s for an Inada granite.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.185-196
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• 2010

Clay veins that occurred in a slope by hydrothermal alteration, can significantly affect its slope stability. The effect of clay veins on the slope stability was investigated by numerical modeling study. Various parameters such as cohesion, internal friction angle, orientation, groundwater level, rainfall intensity and duration, have been modelled. As shear strength increased, factor of safety increased. As groundwater level developed, factor of safety decreased. For the case of slip surface developed on interface, factor of safety was lower than that for case of slip surface developed on either weathered soil or clay vein. The effect of various soil types of the slope stability was also investigated by simulating seepage through the slopes with various soils. The groundwater level significantly increased on the slopes with silty and generic soils. For the slope with sandy soil, almost no change in groundwater level was observed due to rapid drainage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.111-112
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.143-144
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.589-590
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• 2009

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.43-54
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• 2021

Since COVID-19 (Severe acute respiratory syndrome coronavirus type 2, SARS-Cov-2) was first discovered at the end of 2019, it has spread rapidly around the world. This study introduces an agent-based simulation model representing COVID-19 spread in South Korea to investigate the effect of detect level (contact tracing) on the virus spread. To develop the model, related data are aggregated and probability distributions are inferred based on the data. The entire process of infection, quarantine, recovery, and death is schematically described and the interaction of people is modeled based on the traffic data. A composite logistic functions are utilized to represent the compliance of people to the government move control such as social distancing. To demonstrate to effect of detect level on the virus spread, detect level is changed from 0% to 100%. The results indicate active contact tracing inhibits the virus spread and the inhibitory effect increases geometrically as the detect level increases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.913-920
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• 2012

An efficient 3D finite element walking model that considers the detailed shapes of muscles, ligaments, bones, skin, and soles was developed based on a real computed tomography (CT) scan image of a foot, and nonlinear contact analyses were performed to investigate pressure changes. The highest pressure occurs at the rear bottom of the foot when standing and walking. The pressure on the outsole with a curved foot bottom surface is lessened and distributed over a wider area than in the case of a flat outsole. The result shows that a shoe sole shape optimized for diabetes patients can relieve the foot pressure concentration and prevent further worsening of symptoms.